Custom Content Problem

I was following TopHatWaffle's guide for custom content without contamination, but TF2's gameinfo.txt was a tad different, so I looked for a TF2 one. I followed the steps in this tutorial by @sevin and I keep running into the same error I ran into when using tophat's tutorial.

This one message would always pop up, preventing me from opening hammer:
This was with every directory I gave it, no matter which ones I removed.

//This is tf_dev and all of its sub-folders
game+mod tf_dev/*
game+mod tf_dev/content_packs/*
game+mod tf_dev/misc/*
game+mod tf_dev/maps_dev/*

Remember the asterisk modifier makes the preceding folder act like the custom folder, so all those other entries you had were redundant. In the custom folder, you only need 1 outlier folder named whatever you want. Inside that you would have your standard materials, models, sound, etc. So in effect, for example, maps_dev can have your map folder in it, and then the materials folder inside that will be seen and referenced in Hammer. When you specified the materials folder inside the map folder with an asterisk, you're essentially telling Hammer that the materials folder is the custom folder and it's trying to find the next folder inside that to find your materials, which doesn't compute.